What significant event occurred with Fannie Mae and Freddie Mac in 2008?

In 2008, Fannie Mae and Freddie Mac were taken into government conservatorship as a response to the financial crisis that began that year. This significant event was a direct result of their financial difficulties, which stemmed from rising mortgage defaults and the declining real estate market. The conservatorship allowed the Federal Housing Finance Agency (FHFA) to oversee their operations and provide stability to the mortgage market, effectively rescuing these government-sponsored enterprises.

Choosing the option regarding the government conservatorship reflects an understanding of how the U.S. government intervened to manage the crisis in the housing sector, aiming to protect the broader financial system and maintain access to mortgage credit for homeowners and buyers. This action was crucial in stabilizing the economy during a tumultuous time, facilitating recovery efforts in the housing market.

The other options don't accurately represent the major developments concerning Fannie Mae and Freddie Mac during that period, as they did not cease operations, issue new appraisal reporting forms, or limit their mortgage purchases in such a significant way.